This moves all the ptrace hooks related to exec into tracehook.h inlines.

This also lifts the calls for tracing out of the binfmt load_binary hooksinto search_binary_handler() after it calls into the binfmt module. Thischange has no effect, since all the binfmt modules' load_binary functionsdid the call at the end on success, and now search_binary_handler() doesit immediately after return if successful. We consolidate the repeatedcode, and binfmt modules no longer need to import ptrace_notify().